Ce protocole a été testé et optimisé dans le laboratoire du Dr David Scadden. Le financement est assuré par l&#39;Institut Dana Farber Cancer / Hôpital général du Massachusetts Hématologie et d&#39;Oncologie Programme de bourses.

<ol><li> Nous commençons l&#39;expérience homing en extrayant les cellules pour être utilisé dans l&#39;expérience. Pour cette expérience actuelle nous sommes intéressés à savoir si le homing de la moelle osseuse à l&#39;ensemble des niches dans les os longs des animaux receveurs est différent pour les cellules de moelle osseuse extraites d&#39;animaux tels que WT C57BL/6J (WT) et ceux qui sont transgéniques KO pour le récepteur lysophosphatidique 1 (lpar1) (KO). </li><li> Avant de commencer l&#39;expérience, nous allons recueillir les matériaux nous avons besoin pour cette expérience. Dans notre laboratoire tous les dissections de souris sont effectuées dans une hotte à flux laminaire de culture de tissus, surtout si les cellules vont être transplantées dans un animal receveur au lieu d&#39;être utilisé pour l&#39;analyse ex-vivo. Nous commençons par placer une feuille bleue à l&#39;intérieur du capot. D&#39;autres objets nécessaires, notamment une paire de pinces et d&#39;une paire de ciseaux qui ont été autoclavés, un bistouri stérile jetable tampons et l&#39;alcool. Nous aurons besoin de modification du PBS et une stérile 6 plaque de bien, un mortier, un pilon, bleu 50cc surmonté tube conique et d&#39;un filtre 70uM jetables. </li><li> Nous commençons par prendre un WT et une souris KO. </li><li> Ces souris sont euthanasiés par inhalation de CO 2 et ensuite trempés dans 70% isopropranolol pendant 5 secondes. Cette étape empêche la contamination des cellules d&#39;intérêt avec la fourrure de souris et dans nos mains n&#39;a pas mené à aucun compromis sur le rendement des cellules ou des résultats expérimentaux. </li><li> Les souris sont ensuite disséqués à son tour à l&#39;aide d&#39;une paire de pinces et de ciseaux pointus. Nous commençons généralement avec la souris WT comme une affaire de routine. Une petite snip est faite dans la peau ventrale de la souris recouvrant l&#39;abdomen et la peau est ensuite étiré à l&#39;aide des mains. La peau se détache facilement des membres postérieurs. Le fémur et le tibia sont ensuite extraites en prenant soin de ne pas déloger la tête du fémur car il contient une grande quantité de moelle osseuse. Les membres supérieurs sont détachés du torse de l&#39;animal en appliquant simplement la traction pour les tout en gardant le buste immobile. Cela supprime les membres supérieurs comme une seule pièce. L&#39;humérus sont ensuite extraites à partir des membres supérieurs. </li><li> Les os retirés sont placés dans modifiés PBS qui a été ajouté à plaque de 6 puits. Mis à jour le PBS est faite en ajoutant 2 ml de sérum inactivé de la chaleur bovine fœtale et 2 cc d&#39;EDTA 0,5 M pH8. Cette solution est ensuite filtrée à travers un filtre Nalgene 0,45 uM et peuvent être conservés à 4 degrés Celsius pendant au moins un mois. </li><li> Il est essentiel d&#39;étiqueter les puits dans la plaque afin d&#39;être en mesure d&#39;identifier et d&#39;os WT KO correctement. </li><li> Les carcasses de souris sont enlevés et éliminés. </li><li> Une nouvelle feuille est placée dans le capot et les os sont nettoyés en utilisant un scalpel jetable. </li><li> Les os nettoyés sont placés d&#39;une souris à un moment dans le mortier. Deux ml de PBS modifiés est ajoutée à du mortier et les os sont broyés à l&#39;aide d&#39;un pilon. Il est important de premier fragment de l&#39;os avec 10 et vient des mouvements du pilon, puis de les pulvériser avec des mouvements circulaires rotatoire. Je fais habituellement 50 aiguilles d&#39;une montre, puis 50 mouvements anti-horaire et ainsi de suite jusqu&#39;à ce que le matériel laissé dans le mortier est de couleur blanche et le PBS modifiés ajouté à la matière reste blanc ou transparent. </li><li> Après chaque série de 50 mouvements circulaires concassage, nous transférons le fluide de mortier à un filtre 70 uM placé sur le dessus d&#39;un tube conique de 50 ml. Ne pas oublier d&#39;ajouter 2 ml de PBS pour le mortier, après chaque transfert vers le filtre. Vous ne voulez pas essayer de pulvériser les os secs ou les laisser sécher pendant toute la durée du temps que cela va conduire à l&#39;apoptose des cellules. </li><li> Une fois le matériel dans le mortier devient blanche, la matière dans le filtre est transféré au mortier et l&#39;écrasement est à nouveau effectuée. Cela garantit que les cellules dans le filtre ne sont pas gaspillées. Habituellement, cela prend une ou deux séries de mouvements de rotation circulaire, faire à nouveau le matériau de la blanche de mortier de couleur à ce moment de l&#39;extraction de cellules est terminée. </li><li> La solution dans le tube conique est désormais centrifugé (s&#39;il vous plaît n&#39;oubliez pas de garder les cellules de la WT et souris KO séparé. Ainsi, vous aurez deux tubes différents (l&#39;un avec des cellules WT, l&#39;autre avec les cellules KO). Centrifuger à 1200 rpm pendant 10 minutes. </li><li> Aspirer le surnageant à l&#39;aide des pipettes d&#39;aspiration séparée pour chaque tube. Ajouter 2 cc de tampon de lyse ACK à chaque pastille. Ce tampon de lyse doivent être stériles. Incuber dans la glace pendant 5 minutes. </li><li> Ajouter 8 cc de modification du PBS dans chaque tube. Prenez 10 ul de chaque tube et la pipette dans deux puits distincts dans une plaque 96 puits. Placer les tubes dans la centrifugeuse et les faire tourner à 1200 rpm pendant 10 minutes. </li><li> Alors que les tubes sont la filature, ajouter 30 ul d&#39;tryphan colorant bleu et 60 ul d&#39;modifiés PBS dans chaque puits de la plaque de 96 puits qui transporte les cellules d&#39;intérêt. </li><li> Ajouter 10 ul de ce mélange (s&#39;il vous plaît bien mélanger par pipetage de haut en bas) à un hémocytomètre et compter les cellules dans les quatre cases extérieures. </li><li> Le nombre de cellules dans chaque échantillon par ml est le nombre de cellules ainsi compté divisé par 4 et multiplieD par 100 000. </li><li> Une fois la centrifugation est terminée, retirez les tubes de la centrifugeuse et remettre les cellules en PBS sans calcium, de magnésium ou de la glutamine L à une concentration de 20 millions de cellules par ml. Vous aurez probablement environ 5 ml de volume pour le WT et 5 ml de volume pour l&#39;animal KO. A partir de cette étape, nous allons utiliser le PBS, PBS pas modifié pour le protocole. </li><li> Pour chaque tube DII, un colorant coloration des cellules, pour atteindre une concentration finale de 5um. Vortex immédiatement pour 10 secondes. Incuber à 37 degrés pendant 10 minutes et éviter l&#39;exposition à la lumière. </li><li> Remplir les tubes avec du PBS et de spin pendant 10 minutes à 1200 rpm. </li><li> Après centrifugation, aspirer le surnageant et remettre en suspension les cellules dans du PBS à 40 millions de cellules par ml. </li><li> Charge 500 ul dans des seringues de 1 cc avec une aiguille 27G (5 seringues pour la souris WT et 5 seringues pour les souris KO). Il peut être prudent de se préparer 6 seringues pour chaque cohorte. Ayant un extra peut aider que les injections veine de la queue que nous allons faire ensuite peut être délicat. </li><li> Couvrir avec une feuille de seringues afin de garder le DII de se désintégrer. </li><li> Injecter 500 ul du mélange de cellules dans chaque animal receveur; (5 pour chaque cohorte). </li><li> Ces animaux ont besoin d&#39;être irradiés avec 9 Gy d&#39;irradiation 4-24 heures avant l&#39;injection. </li><li> 48 heures après l&#39;injection, la moelle osseuse à partir de récolte des membres postérieurs de chaque animal receveur. </li><li> Procédé tel que décrit ci-dessus pour les donateurs. Resuspendre les cellules de chaque animal dans 1 cc de PBS. Obtenir une numération cellulaire en utilisant un hématimètre. </li><li> Lire sur le cytomètre de flux LSR II de BD ou un instrument équivalent. Le résultat peut être exprimé comme le pourcentage ou le nombre absolu de cellules dans la moelle osseuse qui sont analysés DiI positif. </li></ol>

<ol>
	<li>Adams, G. B., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Stem+cell+engraftment+at+the+endosteal+niche+is+specified+by+the+calcium-sensing+receptor.">Stem cell engraftment at the endosteal niche is specified by the calcium-sensing receptor.</a> Nature. 439 (7076), 599-603 (2006).</li><li>Broxmeyer, H. E. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Chemokines+in+hematopoiesis.">Chemokines in hematopoiesis.</a> Curr Opin Hematol. 15 (1), 49-58 (2008).</li></ol>

Homing est le processus par lequel les cellules de moelle osseuse, y compris les cellules souches, les cellules progénitrices et des cellules différenciées, leur chemin dans la moelle osseuse, après avoir été injecté dans le flux sanguin ou une cavité de moelle osseuse de souris. Comme il est évident à partir de la définition, un scientifique peut choisir d&#39;étudier la domiciliation des cellules souches hématopoïétiques, les cellules progénitrices ou des cellules différenciées identifiés par immuno...

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<td>DPBS (Dulbecco&#x2019;s Phosphate Buffered Saline</td>
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homing of hematopoietic cells to the bone marrow

Homing est le phénomène par lequel les cellules hématopoïétiques transplantés sont capables de se rendre et se greffent ou établir sa résidence dans la moelle osseuse. Chemomkines divers récepteurs sont impliqués dans la domiciliation des cellules souches hématopoïétiques. [1, 2] Ce document décrit le protocole classique de homing utilisés dans les études de cellules souches hématopoïétiques. En général il s&#39;agit d&#39;isoler la population de cellules dont la tête chercheuse doit être étudiée, la coloration de cette population avec un colorant d&#39;intérêt et l&#39;injection de ces cellules dans le sang d&#39;un animal receveur. L&#39;animal receveur est ensuite sacrifié à un moment prédéterminé après l&#39;injection et la moelle osseuse évaluée par le pourcentage ou le nombre absolu de cellules qui sont positifs pour la teinture d&#39;intérêt. Dans l&#39;un des régimes les plus courants expérimentaux, l&#39;efficacité homing des cellules hématopoïétiques à partir de deux animaux génétiquement distinctes (un animal de type sauvage et les correspondants knock-out) est comparé. Cet article décrit le protocole de cellules hématopoïétiques homing dans le cadre de tels que l&#39;expérimentation.

Watch this Scientific Journal Video about Homing of Hematopoietic Cells to the Bone Marrow at JoVE.com

Homing of Hematopoietic Cells to the Bone Marrow

Cet article décrit un protocole utilisé pour étudier le homing des cellules hématopoïétiques à leurs niches dans la moelle osseuse.

Homing des cellules hématopoïétiques de la moelle osseuse

Homing is the phenomenon whereby transplanted hematopoietic cells are able to travel to and engraft or establish residence in the bone marrow.  Various ...

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29.3K vues.  MGH - Massachusetts General Hospital. Cet article décrit un protocole utilisé pour étudier le homing des cellules hématopoïétiques à leurs niches dans la moelle osseuse.

Vidéo: Homing of Hematopoietic Cells to the Bone Marrow

Isolation and Analysis of Hematopoietic Stem Cells from the Placenta

Hematopoietic stem cells (HSCs) have the ability to self-renew and generate all cell types of the blood lineages throughout the lifetime of an individual. All HSCs emerge during embryonic development, after which their pool size is maintained by self-renewing cell divisions. Identifying the anatomical origin of HSCs and the critical developmental events regulating the process of HSC development has been complicated as many anatomical sites participate during fetal hematopoiesis. Recently, we identified the placenta as a major hematopoietic organ where HSCs are generated and expanded in unique microenvironmental niches (Gekas, et al 2005, Rhodes, et al 2008). Consequently, the placenta is an important source of HSCs during their emergence and initial expansion.
In this article, we show dissection techniques for the isolation of murine placenta from E10.5 and E12.5 embryos, corresponding to the developmental stages of initiation of HSCs and the peak in the size of the HSC pool in the placenta, respectively. In addition, we present an optimized protocol for enzymatic and mechanical dissociation of placental tissue into single-cell suspension for use in flow cytometry or functional assays. We have found that use of collagenase for single-cell suspension of placenta gives sufficient yields of HSCs. An important factor affecting HSC yield from the placenta is the degree of mechanical dissociation prior to, and duration of, enzymatic treatment.
We also provide a protocol for the preparation of fixed-frozen placental tissue sections for the visualization of developing HSCs by immunohistochemistry in their precise cellular niches. As hematopoietic specific antigens are not preserved during preparation of paraffin embedded sections, we routinely use fixed frozen sections for localizing placental HSCs and progenitors.

We have identified the placenta as a major hematopoietic organ during development. We found that hematopoietic stem cells (HSCs) are both generated and expanded in the placenta in unique microenvironmental niches. Here, we describe experimental techniques required for isolation and visualization of HSCs in the mouse placenta.

Isolement et analyse de cellules souches hématopoïétiques à partir du placenta

Hematopoietic stem cells (HSCs) have the ability to self-renew and generate all cell types of the blood lineages throughout the lifetime of an individual. ...

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Biologie

Culture of myeloid dendritic cells from bone marrow precursors

Myeloid dendritic cells (DCs) are frequently used to study the interactions between innate and adaptive immune mechanisms and the early response to infection. Because these are the most potent antigen presenting cells, DCs are being increasingly used as a vaccine vector to study the induction of antigen-specific immune responses. In this video, we demonstrate the procedure for harvesting tibias and femurs from a donor mouse, processing the bone marrow and differentiating DCs in vitro. The properties of DCs change following stimulation: immature dendritic cells are potent phagocytes, whereas mature DCs are capable of antigen presentation and interaction with CD4+ and CD8+ T cells. This change in functional activity corresponds with the upregulation of cell surface markers and cytokine production. Many agents can be used to mature DCs, including cytokines and toll-like receptor ligands. In this video, we demonstrate flow cytometric comparisons of expression of two co-stimulatory molecules, CD86 and CD40, and the cytokine, IL-12, following overnight stimulation with CpG or mock treatment. After differentiation, DCs can be further manipulated for use as a vaccine vector or to generate antigen-specific immune responses by in vitro pulsing using peptides or proteins, or transduced using recombinant viral vectors. 

This video demonstrates the procedure for differentiating myeloid dendritic cells from mouse bone marrow. Isolation of mouse tibia and femur, and processing of bone marrow are demonstrated. Pictures demonstrating cell morphology before and after differentiation, and figures depicting cell phenotype and IL-12 production following maturation using CpG are shown.

Culture de cellules dendritiques myéloïdes à partir de précurseurs de moelle osseuse

Myeloid dendritic cells (DCs) are frequently used to study the interactions between innate and adaptive immune mechanisms and the early response to ...

Generation of Bone Marrow Derived Murine Dendritic Cells for Use in 2-photon Imaging

Several methods for the preparation of murine dendritic cells can be found in the literature. Here, we present a method that produces greater than 85% CD11c high dendritic cells in culture that home to the draining lymph node after subcutaneous injection and present antigen to antigen specific T cells (see video). Additionally, we use Essen Instruments Incucyte to track dendritic cell maturation, where, at day 10, the morphology of the cultured cells is typical of a mature dendritic cell and &lt;85% of cells are CD11chigh. The study of antigen presentation in peripheral lymph nodes by 2-photon imaging revealed that there are three distinct phases of dendritic cell and T cell interaction1, 2. Phase I consists of brief serial contacts between highly motile antigen specific T cells and antigen carrying dendritic cells1, 2. Phase two is marked by prolonged contacts between antigen-specific T cell and antigen bearing dendritic cells1, 2. Finally, phase III is characterized by T cells detaching from dendritic cells, regaining motility and beginning to divide1, 2. This is one example of the type of antigen-specific interactions that can be analyzed by two-photon imaging of antigen-loaded cell tracker dye-labeled dendritic cells.

Antigen presentation in secondary lymphoid organs by dendritic cells is crucial for the initiation of the T cell mediated adaptive immune response. Here we demonstrate the culture of bone marrow derived murine dendritic cells, activation, and labeling for 2-photon imaging.

Génération de la moelle osseuse des cellules dendritiques dérivées murin pour l&#39;utilisation dans l&#39;imagerie 2-photons

Several methods for the preparation of murine dendritic cells can be found in the literature. Here, we present a method that produces greater than 85% ...

The Preparation of Primary Hematopoietic Cell Cultures From Murine Bone Marrow for Electroporation

It is becoming increasingly apparent that electroporation is the most effective way to introduce plasmid DNA or siRNA into primary cells. The Gene Pulser MXcell  electroporation system and Gene Pulser  electroporation buffer were specifically developed to transfect nucleic acids into mammalian cells and difficult-to-transfect cells, such as primary and stem cells.This video demonstrates how to establish primary hematopoietic cell cultures from murine bone marrow, and then prepare them for electroporation in the MXcell system. We begin by isolating femur and tibia. Bone marrow from both femur and tibia are then harvested and cultures are established. Cultured bone marrow cells are then transfected and analyzed.

This procedure describes how to establish primary hematopoietic cell cultures from murine bone marrow and is followed by transfection using the Gene Pulser MXCell electroporation system.

La préparation des cultures primaires de cellules hématopoïétiques de la moelle osseuse murine pour l&#39;électroporation

It is becoming increasingly apparent that electroporation is the most effective way to introduce plasmid DNA or siRNA into primary cells. The Gene Pulser ...

Lentiviral-mediated Knockdown During Ex Vivo Erythropoiesis of Human Hematopoietic Stem Cells

Erythropoiesis is a commonly used model system to study cell differentiation. During erythropoiesis, pluripotent adult human hematopoietic stem cells (HSCs) differentiate into oligopotent progenitors, committed precursors and mature red blood cells 1. This process is regulated for a large part at the level of gene expression, whereby specific transcription factors activate lineage-specific genes while concomitantly repressing genes that are specific to other cell types 2. Studies on transcription factors regulating erythropoiesis are often performed using human and murine cell lines that represent, to some extent, erythroid cells at given stages of differentiation 3-5. However transformed cell lines can only partially mimic erythroid cells and most importantly they do not allow one to comprehensibly study the dynamic changes that occur as cells progress through many stages towards their final erythroid fate. Therefore, a current challenge remains the development of a protocol to obtain relatively homogenous populations of primary HSCs and erythroid cells at various stages of differentiation in quantities that are sufficient to perform genomics and proteomics experiments.
Here we describe an ex vivo cell culture protocol to induce erythroid differentiation from human hematopoietic stem/progenitor cells that have been isolated from either cord blood, bone marrow, or adult peripheral blood mobilized with G-CSF (leukapheresis). This culture system, initially developed by the Douay laboratory 6, uses cytokines and co-culture on mesenchymal cells to mimic the bone marrow microenvironment. Using this ex vivo differentiation protocol, we observe a strong amplification of erythroid progenitors, an induction of differentiation exclusively towards the erythroid lineage and a complete maturation to the stage of enucleated red blood cells. Thus, this system provides an opportunity to study the molecular mechanism of transcriptional regulation as hematopoietic stem cells progress along the erythroid lineage. 
Studying erythropoiesis at the transcriptional level also requires the ability to over-express or knockdown specific factors in primary erythroid cells. For this purpose, we use a lentivirus-mediated gene delivery system that allows for the efficient infection of both dividing and non-dividing cells 7. Here we show that we are able to efficiently knockdown the transcription factor TAL1 in primary human erythroid cells. In addition, GFP expression demonstrates an efficiency of lentiviral infection close to 90%. Thus, our protocol provides a highly useful system for characterization of the regulatory network of transcription factors that control erythropoiesis.

Lentiviral-mediated Knockdown During Ex Vivo Erythropoiesis of Human Hematopoietic Stem Cells

An ex vivo protocol to generate mature human red blood cells from hematopoietic stem/progenitors is described. Additionally we describe an efficient lentiviral-delivery method to knockdown the transcription factor TAL1 in primary erythroid cells. The efficiency of lentivirus mediated gene delivery is demonstrated using GFP expressing viruses.

Lentiviraux médiée Knockdown cours Ex Vivo</emÉrythropoïèse> des cellules souches hématopoïétiques humaines

Erythropoiesis is a commonly used model system to study cell differentiation. During erythropoiesis, pluripotent adult human hematopoietic stem cells ...

In Vivo 4-Dimensional Tracking of Hematopoietic Stem and Progenitor Cells in Adult Mouse Calvarial Bone Marrow

Through a delicate balance between quiescence and proliferation, self renewal and production of differentiated progeny, hematopoietic stem cells (HSCs) maintain the turnover of all mature blood cell lineages. The coordination of the complex signals leading to specific HSC fates relies upon the interaction between HSCs and the intricate bone marrow microenvironment, which is still poorly understood[1-2].
We describe how by combining a newly developed specimen holder for stable animal positioning with multi-step confocal and two-photon in vivo imaging techniques, it is possible to obtain high-resolution 3D stacks containing HSPCs and their surrounding niches and to monitor them over time through multi-point time-lapse imaging. High definition imaging allows detecting ex vivo labeled hematopoietic stem and progenitor cells (HSPCs) residing within the bone marrow. Moreover, multi-point time-lapse 3D imaging, obtained with faster acquisition settings, provides accurate information about HSPC movement and the reciprocal interactions between HSPCs and stroma cells.
Tracking of HSPCs in relation to GFP positive osteoblastic cells is shown as an exemplary application of this method. This technique can be utilized to track any appropriately labeled hematopoietic or stromal cell of interest within the mouse calvarium bone marrow space.

In Vivo 4-Dimensional Tracking of Hematopoietic Stem and Progenitor Cells in Adult Mouse Calvarial Bone Marrow

The nature of the interactions between hematopoietic stem and progenitor cells (HSPCs) and bone marrow niches is poorly understood. Custom hardware modifications and a multi-step acquisition protocol allow the use of two-photon and confocal microscopy to image ex vivo labeled HSPCs homed within bone marrow areas, tracking interactions and movement.

In Vivo suivi 4-Dimensional de hématopoïétiques cellules souches et progénitrices adultes dans la voûte du crâne de souris de moelle osseuse

Through a delicate balance between quiescence and proliferation, self renewal and production of differentiated progeny, hematopoietic stem cells (HSCs) ...

Osteoclast Derivation from Mouse Bone Marrow

Osteoclasts are highly specialized cells that are derived from the monocyte/macrophage lineage of the bone marrow. Their unique ability to resorb both the organic and inorganic matrices of bone means that they play a key role in regulating skeletal remodeling. Together, osteoblasts and osteoclasts are responsible for the dynamic coupling process that involves both bone resorption and bone formation acting together to maintain the normal skeleton during health and disease.
As the principal bone-resorbing cell in the body, changes in osteoclast differentiation or function can result in profound effects in the body. Diseases associated with altered osteoclast function can range in severity from lethal neonatal disease due to failure to form a marrow space for hematopoiesis, to more commonly observed pathologies such as osteoporosis, in which excessive osteoclastic bone resorption predisposes to fracture formation.
An ability to isolate osteoclasts in high numbers in vitro has allowed for significant advances in the understanding of the bone remodeling cycle and has paved the way for the discovery of novel therapeutic strategies that combat these diseases. 
Here, we describe a protocol to isolate and cultivate osteoclasts from mouse bone marrow that will yield large numbers of osteoclasts.

Osteoclasts are the principal bone-resorbing cell in the body. An ability to isolate osteoclasts in large numbers has resulted in significant advances in the understanding of osteoclast biology. In this protocol, we describe a method for isolation, cultivating and quantifying osteoclast activity in vitro.

Ostéoclastes Dérivation de moelle osseuse de souris

Osteoclasts are highly specialized cells that are derived from the monocyte/macrophage lineage of the bone marrow. Their unique ability to resorb both the ...

Expression of Fluorescent Fusion Proteins in Murine Bone Marrow-derived Dendritic Cells and Macrophages

Dendritic cells and macrophages are crucial cells that form the first line of defense against pathogens. They also play important roles in the initiation of an adaptive immune response. Experimental work with these cells is rather challenging. Their abundance in organs and tissues is relatively low. As a result, they cannot be isolated in large numbers. They are also difficult to transfect with cDNA constructs. In the murine model, these problems can be partially overcome by in vitro differentiation from bone marrow progenitors in the presence of M-CSF for macrophages or GM-CSF for dendritic cells. In this way, it is possible to obtain large amounts of these cells from very few animals. Moreover, bone marrow progenitors can be transduced with retroviral vectors carrying cDNA constructs during early stages of cultivation prior to their differentiation into bone marrow derived dendritic cells and macrophages. Thus, retroviral transduction followed by differentiation in vitro can be used to express various cDNA constructs in these cells. The ability to express ectopic proteins substantially extends the range of experiments that can be performed on these cells, including live cell imaging of fluorescent proteins, tandem purifications for interactome analyses, structure-function analyses, monitoring of cellular functions with biosensors and many others. In this article, we describe a detailed protocol for retroviral transduction of murine bone marrow derived dendritic cells and macrophages with vectors coding for fluorescently-tagged proteins. On the example of two adaptor proteins, OPAL1 and PSTPIP2, we demonstrate its practical application in flow cytometry and microscopy. We also discuss the advantages and limitations of this approach.

In this article, we provide a detailed protocol for the expression of fluorescent fusion proteins in murine bone marrow derived dendritic cells and macrophages. The method is based on the transduction of bone marrow progenitors with retroviral constructs followed by differentiation into macrophages and dendritic cells in vitro.

Expression des protéines de Fusion Fluorescent en Murine dérivés de la moelle osseuse des cellules dendritiques et Macrophages

Dendritic cells and macrophages are crucial cells that form the first line of defense against pathogens. They also play important roles in the initiation ...

Isolation, Purification, and Differentiation of Osteoclast Precursors from Rat Bone Marrow

Osteoclasts are large, multinucleated, and bone-resorbing cells of the monocyte-macrophage lineage that are formed by the fusion of monocytes or macrophage precursors. Excessive bone resorption is one the most significant cellular mechanisms leading to osteolytic diseases, including osteoporosis, periodontitis, and periprosthetic osteolysis. The main physiological function of osteoclasts is to absorb both the hydroxyapatite mineral component and the organic matrix of bone, generating the characteristic resorption appearance on the surface of bones. There are relatively few osteoclasts compared to other cells in the body, especially in adult bones. Recent studies have focused on how to obtain more mature osteoclasts in less time, which has always been a problem. Several improvements in the isolation and culture techniques have developed in laboratories in order to obtain more mature osteoclasts. Here, we introduce a method that isolates bone marrow in less time and with less effort compared to the traditional procedure, using a special and simple device. With the use of density gradient centrifugation, we obtain large amounts of fully differentiated osteoclasts from rat bone marrow, which are identified by classical methods.

Osteoclasts are tissue-specific macrophage polykaryons derived from the monocyte-macrophage lineage of hematopoietic stem cells. This protocol describes how to isolate bone marrow cells so that large quantities of osteoclasts are obtained while reducing the risk of accidents found in traditional methods.

Isolement, purification et différenciation des précurseurs d’Ostéoclast de la moelle osseuse de rat

Osteoclasts are large, multinucleated, and bone-resorbing cells of the monocyte-macrophage lineage that are formed by the fusion of monocytes or ...

Proplatelet Formation Dynamics of Mouse Fresh Bone Marrow Explants

The last stage of megakaryopoiesis leads to cytoplasmic extensions from mature megakaryocytes, the so-called proplatelets. Much has been learned about the proplatelet formation using in vitro-differentiated megakaryocytes; however, there is an increasing evidence that conventional culture systems do not faithfully recapitulate the differentiation/maturation process that takes places inside the bone marrow. In this manuscript, we present an explant method initially described in 1956 by Thi&#233;ry and Bessis to visualize megakaryocytes which have matured in their native environment, thus circumventing potential artifacts and misinterpretations. Fresh bone marrows are collected by flushing the femurs of mice, sliced into 0.5 mm cross sections, and placed in an incubation chamber at 37 &#176;C containing a physiological buffer. Megakaryocytes become gradually visible at the explant periphery and are observed up to 6 hours under an inverted microscope coupled to a video camera. Over time, megakaryocytes change their shape, with some cells having a spherical form and others developing thick extensions or extending many thin proplatelets with extensive branching. Both qualitative and quantitative investigations are carried out. This method has the advantage of being simple, reproducible, and fast as numerous megakaryocytes are present, and classically half of them form proplatelets in 6 hours compared to 4 days for cultured mouse megakaryocytes. In addition to the study of mutant mice, an interesting application of this method is the straightforward evaluation of the pharmacological agents on the proplatelet extension process, without interfering with the differentiation process that may occur in cultures.

Here, we detail the bone marrow explant method, from sample preparation to microscopic slide analysis, to evaluate the ability of megakaryocytes which have differentiated in their physiological environment to form proplatelets.

Dynamique de formation proplaquettaire des explants de moelle osseuse fraîche de souris

The last stage of megakaryopoiesis leads to cytoplasmic extensions from mature megakaryocytes, the so-called proplatelets. Much has been learned about the ...